14 сентября, 2015 
Malyar T. M. Goulding
Consultant, Johannesburg, South Africa
Epoxy or epoxide resins are a group of reactive compounds that are characterized by the presence of the oxirane group
They are capable of reacting with suitable hardeners to form cross-linked matrices of great strength and with excellent adhesion to a wide range of substrates. This makes them ideally suited to adhesive applications in which high strength under adverse conditions is a prerequisite. Their unique characteristics include negligible shrinkage during cure, an open time equal to the usable life, excellent chemical resistance, ability to bond nonporous substrates, and great versatility. Although they were hailed as wonder products when first introduced, it has now been accepted that they will not do everything. They have, however, clearly established niches, especially in high-technology applications, and have shown steady growth, generally ahead of the industry average. Sales of epoxy resins in Europe, for example, totaled 101,000 metric tons in 1980, 150,000 metric tons in 1985, and 205,000 metric tons in 1990.
Although work on epoxy resins started in the mid-1920s, the first commercially useful epoxy resins appeared during World War II. These were based on the diglycidyl ether of bisphenol A (usually referred to as DGEBA resins), and today these resins, in a range of molecular weights, constitute the majority of all epoxy resins used. By contrast, however, hardeners come in a variety of shapes and sizes, including amines and amides, mercaptans, anhydrides, and Lewis acids and bases. Choice of hardener depends on the application requirements, and the wide range of hardeners available increases the versatility of adhesives based on epoxy resins.
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